The present invention relates to a semiconductor device having an AD (Analog-to-Digital) converter.
A semiconductor device (for example, a microcomputer) having therein an AD converter can detect, as digital values, an external input analog voltage, an internal reference voltage value output from a reference voltage generating circuit, an output value of an internal temperature sensor circuit, and the like. The AD converter is used, for example, by a method of monitoring chip environments by periodically AD converting the internal reference voltage value and the output value of the temperature sensor circuit while repeatedly AD converting the external input voltage.
There are also techniques that, in a semiconductor device having an AD converter, charges accumulated in a sample and hold capacitor are discharged and, after that, signal coupling is switched.